The invention relates to an apparatus for making available or dispensing a leno thread for a weaving machine.
An apparatus for making available a leno thread is known from the patent specification EP 1 052 317 A1. Disadvantageous in this apparatus is the fact that a large amount of space is required and that during the drawing off of the leno thread a plurality of windings sometimes come off at the same time.
The object of the present invention is to propose an advantageous apparatus for making available a leno thread.
This object is satisfied in particular by an apparatus for making available a leno thread for a weaving machine, comprising a shaft which is rotatably journalled about an axis of rotation and which has an active connection to a drive apparatus in order to set the shaft into rotation, and comprising a holder apparatus for accommodating a leno thread bobbin, with the holder apparatus being rotatably connected to the shaft, and comprising a holder means for the substantially rotation-free holding of the holder apparatus, and comprising a thread guiding element which is firmly connected to the shaft, with the holder apparatus being designed for the accommodation of at least two leno thread bobbins and with the shaft having a thread guiding passage which opens towards the holder apparatus and which is designed in such a manner that both leno warp threads passing through the thread guiding passage can be introduced to the thread guiding element.
The apparatus in accordance with the invention has the advantage that both leno thread bobbins are arranged in the same holder apparatus, which enables a short and compact constructional form. In a preferred embodiment the apparatus in accordance with the invention is designed for the accommodation of two leno thread bobbins. This apparatus can however have more than two holder apparatuses for leno thread bobbins. In a preferred embodiment the apparatus for preparing the leno threads has a thread guiding passage which opens into the center of the holder apparatus, via which all leno threads are drawn off. The thread guiding passage is followed by a thread guiding element which is journalled so as to be capable of being driven and rotated through 360xc2x0 about an axis of rotation. The design of the thread guiding element and the direction of the path of the leno threads is such that the leno threads are drawn off from the leno thread bobbins via the thread guiding passage and the leno threads are then supplied to the weaving machine while circulating outwardly about the holder apparatus. This circulatory movement leads to a mutual twisting of the leno threads which are drawn off from the leno thread bobbins. A thread twisting element is also subsequently provided which supplies the mutually twisted leno threads to a following weaving machine in synchronism with its working cycle, so that a leno edge or a leno binding respectively can be produced in the cloth. The apparatus in accordance with the invention enables a complete leno binding to be produced.
One advantage of the apparatus in accordance with the invention is the fact that the holder apparatus for the leno thread bobbins is designed to be stationary or substantially stationary. This enables the apparatus in accordance with the invention to be operated with a very high speed of rotation as well. In addition the movably journalled thread guiding element can be designed to be very light, i.e. to have low mass, which in addition to a high speed of rotation also permits a rapid moving out and braking of the thread guiding element.
The invention will be described with reference to a plurality of exemplary embodiments.